1. Field of the Invention
This invention relates broadly to clamping devices used in orthopedic surgery and more specifically to clamps which are used temporarily during the surgery procedure and removed prior to the completion of surgery. The orthopedic surgeon frequently encounters fractures in which he desires to maintain alignment of the bone fragments by installing a screw, plate, pin or wire across the fracture. Such a plate or pin may be either temporary, to be removed after the healing of the fracture, or permanently left at the fracture site. Regardless of the specific nature of this type of repair, it is important to clamp the bone fragments together while such a plate or pin is being installed in order that the bone fragments may be maintained in alignment and in order that no gaps exist which could increase the chances of non-union. The situation would be most critical when, after a bone plate is fixed to one bone fragment, the plate is about to be fixed to a second bone fragment. Because of the downward pressure applied by the surgeon when installing a bone screw, the second bone fragment is liable to become misaligned with respect to the other bone fragment. Because of the use of bone screws, such misalignment would be difficult to correct because of the nature of the screw hole.
2. Description of the Prior Art
A number of efforts have been made in the prior art to provide bone-clamping apparatus for use during a surgical procedure. A device represented by U.S. Pat. No. 1,985,108 to Rush uses opposed curved clamping fingers to engage two sides of a bone during the insertion of a plate. This arrangement is intended to be placed around the bone in order to align the bone along its axis, as opposed to longitudinal compression. Various other clamps have been proposed which surround a fractured bone in order to provide temporary support for the bone while the bone is being repaired. One surgeon even adapted a pair of curved plate-like jaws to a pair of Vice Grips (Trademark for a type of locking jaw pliers) for the purpose of clamping fractured bones.
In addition to a Vice Grips (TM) arrangement, thumbscrew arrangements and ratcheting handles have been used to hold the bone clamps in a clamping position. An example of a thumbscrew arrangement is shown in the above-mentioned Rush patent. A ratcheting arrangement is exemplified by U.S. Pat. No. 4,009,712 to Burstein, et al.
The use of inwardly-turned ends for effecting bone clamping is known. For example, U.S. Pat. No. 4,201,215, to Crossett, et al., shows the use of inwardly-turned ends.
In the prior art it was usually necessary to provide clearance around a temporary clamp in order to perform surgical procedures, such as screwing on a bone plate. In cases, such as when using the above-mentioned Rush patent, where a bone plate is either held in position or where the position of the bone plate is closely determined by the position of the clamp, the clamp could be constructed so as to clear a specified path for the surgeon, such as when a screwdriver was used to insert bone screws. In any case, most of the prior art apparatus provided for surgical access by having handles which, when the clamp was inserted onto a bone, were hopefully out of the way of surgical procedures.
Additionally, most of the prior art bone clamps required a substantial area of the bone to be exposed. This is particularly true in cases where curvate plate-like jaws wrap around a bone. If the fracture site happens to occur in the vicinity of the nutrient artery or at a similar critical location, extreme care must be taken to avoid damaging the tissue at this area. This can present a problem when the nutrient artery is located behind an incision site and must be avoided as the bone is exposed from behind.
In many cases, the fracture site occurs at the end of a long bone, such as the end of the tibia or ulna or in one of the short irregular bones. In such cases, it may be difficult to grip both sides of the fracture with a bone clamp which is designed to surround the shaft of a long bone, in part because of the more irregular shape of the bone at this area.